In the last section, we only considered the line-based Pareto fronts in three dimensions and showed that the hypervolume optimal \(\mu \) -distribution is not always uniform on these Pareto fronts. In this section, we investigate plane-based Pareto fronts, which are more commonly seen in multi-objective optimization test problems (e.g., three-objective DTLZ1 [1]} and DTLZ1\(^{-1}\)  [2]}).
